* {
    box-sizing: border-box;
}
html,body,#app, .page {
    font-family: Avenir, Helvetica, Arial, sans-serif;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    width: 100%;
    height: 100%;
    overflow: hidden;
}
.page {
    overflow: auto;
}
.back-common {
    background-repeat: no-repeat;
    background-position: center center;
    background-size: 100%;
}